1. Field of the Invention
This invention relates to a gravure engraver and, more particularly, to an engraver having a real-time tool path virtual proofing system and method.
2. Description of the Related Art
The gravure printing process is an additive process which typically involves at least four colors and henceforth cylinders, one for each color (yellow, magenta, cyan and black or key). It is not uncommon that spot colors are used, in addition, to obtain a very consistent color, such as the orange color used on a Tide® detergent box. To create a composite test proof, each cylinder is inked and used to print on a substrate. Registering the cylinders and performing the test proof substrate is, again, very time consuming and labor intensive. Thus, traditional workflow of gravure printing involves creating a full color proof on a proof press prior to the engraved cylinders being released to high volume production press. Creating a full color test proof is an expensive and time consuming process. This also puts gravure printing at a disadvantage compared to other types of printing processes, such as flexographic printing.
Proof presses are used as a quality check prior to committing the cylinders to production. The process involves the following steps for each of the YMCK cylinders: using a crane to install the cylinder in the proof press, aligning the cylinder to the substrate, aligning the doctor blade for wiping the ink, mixing the ink to ensure proper viscosity, inking the cylinder, running this one color print, cleaning the cylinder and doctor blade of excess ink, and removing the cylinder. These steps are repeated for each color where each color is registered to previous colors to obtain the desired composite image. Performing these steps for four colors takes an experienced operator one or more hours. Most, if not all, gravure cylinder facilities have multiple proofing presses and employ dedicated people for this quality step. As is apparent, the process is time consuming and expensive.
Different approaches for eliminating the expensive proofing step have been sought after for many years. For example, capturing images of the engraved pattern using cameras and other techniques to provide an optical or visual inspection of the cylinders has been attempted in the past. An Israeli company, PSik Solutions, Ltd., offered the idea of an optical visual inspection system in 2011, but the implementation has not been economically practical. Unfortunately, these approaches are impractical due to the image capture and computer processing speed limitations. Although theoretically possible, the development costs for such a system is prohibitive for this market. These approaches are also expensive and oftentimes require large amounts of processing capability.
Accordingly, there is a need for an improved proofing system and method that reduces or eliminates traditional proofing processes of the past.